<div id="banner">
	<div class="por_img">
	</div>
</div>
<script type="text/javascript">
	//<!CDATA[
	var bodyBgs = [];
	bodyBgs[0] = "{ms:global.host/}/{ms:global.style/}images/s1.jpg";
	bodyBgs[1] = "{ms:global.host/}/{ms:global.style/}images/s2.jpg";
	bodyBgs[2] = "{ms:global.host/}/{ms:global.style/}images/s3.jpg";
	bodyBgs[3] = "{ms:global.host/}/{ms:global.style/}images/s4.jpg";
	bodyBgs[4] = "{ms:global.host/}/{ms:global.style/}images/s5.jpg";
	var randomBgIndex = Math.round(Math.random() * 4);
	//输出随机的背景图
	document.write('<style>.por_img{background:url(' + bodyBgs[randomBgIndex] + ') no-repeat 50% bottom}</style>');
	//]]>
</script>